兵马俑博物馆冬季室内大气悬浮颗粒物与游客数量的关系

通过对秦始皇兵马俑博物馆铜车马展厅和一号坑室内采集的冬季大气悬浮颗粒物进行单颗粒分析,评价了在具有不同通风条件的两个展厅中,游客数量对大气悬浮颗粒物的影响。研究中采用配备能谱的扫描电子显微镜对单颗粒进行了形貌和元素组成分析,以判断室内悬浮颗粒的来源和化学组成差异,同时监测了两个展厅室内的微环境变化。结果显示,在铜车马展厅室内悬浮颗粒的昼夜质量浓度之比(1.30～3.12),明显高于同期的一号坑(0.96～2.59)和室外(0.68～1.79),表明在铜车马展厅游客数量对颗粒物质量浓度的贡献大于在一号坑内。室内、外对比的结果表明,悬浮颗粒物的质量浓度、粒径分布和颗粒类型等特性,在配备了机械通风设备的铜车马展厅中受游客数量的影响较大,而在自然通风为主的一号坑中,通风条件则成为决定因素。颗粒物组成分析显示,博物馆冬季的室内悬浮颗粒主要由黄土中的矿物颗粒、烟炱等低原子序数的颗粒、硫酸盐、燃煤飞灰和生物质颗粒组成。除烟炱和铝硅酸盐会造成对文物的脏污外,随着温、湿度的波动,硫酸钙的结晶、溶解、渗透和再结晶作用都会产生应力,导致兵马俑表面的风化。

Relationship Between Tourist Flow and Indoor Airborne Particles in the Museum of the Terracotta Army

The daytime and nighttime total suspended particulate matters (TSP)were collected inside and outside the bronze chariots,horses exhibition hall(BCH)and Pit No. 1 Exhibition hall(Pit 1)of the Museum of the Terracotta Army (MTA) in winter,2008. The purpose of this research was to study the contribution of visitors on indoor airborne particles in two display halls with distinguishing ventilating conditions in MTA. The morphological and elemental analyses of individual particles were performed with scanning electron microscopy and energy dispersive X-ray spectrometer to determine the source of particles and their chemical changes. The microclimate inside the two display halls was also monitored. In most sampling days with intensive tourist visits,the daytime/nighttime particle mass ratios in BCH(1.30～3.12) were higher than those in Pit 1 (0.96～2.59) and outdoors (0.68～1.79), indicting more contribution of the tourist flow on particle mass concentrations in BCH than in Pit 1. The difference between indoor and outdoor particle mass concentrations,number particle size distribution and particle types were found in close relationship with visitor numbers in BCH equipped with a mechanical ventilating system,and with ventilating condition in Pit No.1 relying on natural ventilation. Indoor airborne particles in winter were composed of loess mineral dusts, low Z(atomic number) particles, sulfates, fly ashes and biological particles. Besides soiling hazard posed by soot and aluminosilicate,crystallization, dissolution,penetration and recrystallization of deposited calcium sulfates with the fluctuation of relative humidity and temperature might produce stress,thereby causing weathering on the surface of the terracotta statues.